Expanding joint for an initially substantially planar member

摘要

An expanding joint is disclosed for increasing the size of an initially substantially planar member, upon stretching. The joint includes a discontinuous incision having a sinusoidal pattern extending transversely on an axis extending normal to the direction of stretching and being arranged in alternating concave and convex portions. Each of the concave and convex portions are discretely separated from the portions by an isthmus such that the incision widens upon application of tension in a direction substantially normal to the axis.